1. Field of the Invention
This invention concerns treatment of waste anesthetic gas. In particular the invention pertains to the removal and reclamation of nitrous oxide, fluoro-ethers, and other halocarbons from waste anesthetic gas of a healthcare facility before the gas is discharged to the atmosphere in order to decrease atmospheric pollution.
2. Description of the Prior Art
The administration of anesthesia in surgical and other healthcare facilities creates significant quantities of waste anesthetic gases. Currently these gases are scavenged, diluted with air in a system of dedicated pipes, and then vented to the atmosphere outside the building. The average composition of the waste gases is estimated to be (in percent volume) 25-32 percent oxygen, 60-65 percent nitrogen, 5-10 percent nitrous oxide, and 0.1-0.5 percent other volatile halocarbons, including fluoro-ethers such as isoflurane, desflurane and sevoflurane.
The halocarbons (primarily halogenated ethers) represent an increasingly significant source of environmental concern, because other halocarbon emissions have recently been reduced by legislative and other initiatives. These compounds (similar to refrigerants Freon-12® and others) can contribute to ozone depletion and environmental warming. Although it is anticipated that regulation of these emissions will occur in the near future, currently no such regulation exists.
Several techniques have been employed to treat waste anesthetic gases. U.S. Pat. No. 4,259,303 describes treating laughing gas with a catalyst. Adsorption of anesthetic gases by charcoal granules is described in U.S. Pat. No. 5,044,363. Destruction of anesthetic gases by heating in the presence of a catalyst is described in U.S. Pat. Nos. 5,759,504 and 6,134,914 issued to Eschwey et al. describes a process for separating xenon from exhaled anesthetic gas, and U.S. Pat. No. 6,729,329 issued to Berry describes a method for removing halocarbons from waste anesthetic gas.
3. Identification of Objects of the Invention
A primary object of the invention is to provide an economical system and method for removing fluoro-ethers and other volatile halocarbons from waste anesthetic gases from a surgical facility before such gases are vented to the atmosphere.
Another object of the invention is to provide an economical system and method for removing nitrous oxide from waste anesthetic gases from a surgical facility before such gases are vented to the atmosphere.
Another object of the invention is to provide an economical system and method for substantially preventing the atmospheric venting of fluoro-ethers and other volatile halocarbons of waste anesthetic gases while eliminating the need of prior art catalysts, charcoal granules and heating techniques.
Another object of the invention is to provide an economic system and method for separating various removed nitrous oxide, fluoro-ethers, and other volatile halocarbon components based on their physical characteristics.
Another object of the invention is to provide an economical system and method which increases a healthcare facility's overall energy efficiency by utilizing existing liquefied gas storage and delivery systems.
Another object of the invention is to provide an economical system and method which minimizes the impact of reclamation system installation on the healthcare facility by utilizing existing liquefied gas storage and delivery systems.
Another object of the invention is to provide a system and method which requires minimal additional investment for a healthcare facility to implement.
Another object of the invention is to provide a system and method which reclaims and allows re-distillation and/or reuse of a large percentage of the nitrous oxide and/or anesthetic halocarbons used in the facility.
Another object of the invention is to provide a system and method which reduces anesthetic-related halocarbon emissions from a healthcare facility into the atmosphere by about 99 percent or more.